Computed tomography and tomosynthesis system

Abstract

A computed tomography system, capable of tomosynthesis, includes an inner circular gantry and an outer gantry within a housing assembly. A plurality of spaced apart radiology imaging plates are located along the inner gantry and adapted as x-ray detectors. An x-ray source is secured to the outer gantry and adapted to shoot x-rays between the spaced apart detectors and onto the patient or object while being rotated along the gantry and relative to the patient. A radiography device is moveably coupled to the inner gantry and adapted to scan and read the radiology plates and provide the data to an image processing computer. The x-ray source coupled to the outer gantry moves relative to the imaging plates such that a large number of projections can be exposed and thereafter scanned by the integral radiology device.

What is claimed is: 
     
       1. A computed tomography system comprising:
 (a) a housing assembly defining a tubular cavity about a perpendicular axis; 
 (b) a tubular outer hoop assembly mounted within the housing about the perpendicular axis; 
 (c) a tubular inner hoop assembly supporting a plurality of spaced apart x-ray photostimulable detector members, the inner hoop assembly rotatably coupled to the housing about the perpendicular axis and inside the outer hoop assembly; 
 (d) an x-ray source adapted to expose an object within the tubular cavity with x-ray energy, the x-ray source moveably coupled to the outer hoop assembly and adapted to move about a common arc with the outer hoop assembly and expose objects located within the tubular cavity; 
 (e) a computed radiography device mounted within the housing between the inner hoop assembly and the outer hoop assembly and adapted for scanning at least one of the x-ray detector members and for acquiring x-ray energy from the detector members and wherein said computer radiography device utilizes a scan head for such scanning; 
 (f) a first drive apparatus adapted for rotating the detector means about the tubular cavity relative to the radiography device; 
 (g) a second drive apparatus adapted for moving the x-ray source along the common arc about the tubular cavity; 
 (h) wherein the inner hoop and x-ray source are independently rotatable about the tubular cavity to expose the object with x-rays from a plurality of perspectives; and 
 (i) wherein when the inner hoop assembly is rotated relative to the housing, the detector members are rotated relative to and adjacent the radiography device allowing the radiography device to acquire any retained x-ray exposure energy from the adjacent detector member. 
 
     
     
       2. The computed tomography system of  claim 1  wherein the photostimulable detector members comprise a plurality of photostimulable plates secured to an outer surface of the inner hoop assembly. 
     
     
       3. The computed tomography system of  claim 2  wherein the computed radiography device is adapted to erase the x-ray energy stored in at least one of the photostimulable plates. 
     
     
       4. The computed tomography system of  claim 2  wherein the computed radiography device is adapted to function as a direct radiography system. 
     
     
       5. The computed tomography system of  claim 2  wherein the computed radiography device is fixed to the housing and the inner hoop assembly rotates at least one detector member adjacent the scan head. 
     
     
       6. The computed tomography system of  claim 5  wherein the object is exposed to x-ray energy from the x-ray source at substantially the same time that the computed radiography device is scanning a detector member. 
     
     
       7. The computed tomography system of  claim 1  wherein the detector members comprise a plurality of photostimulable plates mounted within cassettes that are removeably secured to the inner hoop assembly. 
     
     
       8. The computed tomography system of  claim 1  wherein the detector members comprise a plurality of digital detector panels secured to the inner hoop assembly. 
     
     
       9. The computed tomography system of  claim 1  wherein the inner hoop assembly rotates about the tubular cavity at a different speed than the x-ray source rotates about the tubular cavity. 
     
     
       10. A computed tomosynthesis system comprising:
 (a) a tubular gantry assembly having a cylindrical inner hoop assembly positioned within a larger outer cylindrical hoop assembly and a plurality of side plates coupling the inner and outer hoop assemblies and defining a cylindrical cavity there between, the gantry assembly adapted for receiving and passing an object within a tubular cavity defined inside the inner hoop assembly; 
 (b) an x-ray source coupled to said outer hoop assembly and adapted for emitting x-ray energy through an object placed within the tubular cavity; 
 (c) a plurality of spaced apart photostimulable storage phosphor surfaces coupled to an outer surface of the inner hoop assembly and adapted to receive the x-rays passing thought the object; 
 (d) a computed radiography device having a scan head, the computed radiography device coupled to the gantry assembly between the inner hoop and the outer hoop and adapted for scanning the storage phosphor surfaces to acquire images from the stored x-ray energy; 
 (e) an inner hoop drive assembly adapted to rotate the phosphor surfaces about the tubular cavity and relative to the scan head wherein the computed radiography device can acquire the stored x-ray energy; and 
 (f) an x-ray source drive adapted to move the x-ray source about an arc having a common perpendicular axis with the tubular cavity; and 
 (g) wherein the inner hoop assembly is rotatable about the tubular cavity and relative to the outer hoop assembly. 
 
     
     
       11. The computed tomosynthesis system of  claim 10  wherein the photostimulable storage phosphor surfaces a needle phosphor. 
     
     
       12. The computed tomosynthesis system of  claim 10  wherein the computed radiography device and the storage phosphor surfaces are adapted for use in non-destructive testing. 
     
     
       13. The computed tomosynthesis system of  claim 10  wherein the x-ray source is moveable about an arc having a rotational axis in the tubular cavity such that x-ray exposures can be taken of the object from a plurality of locations along the arc. 
     
     
       14. The computed tomosynthesis system of  claim 10  wherein the object is exposed to x ray energy from the x-ray source at substantially the same time that the computed radiography device is scanning a storage phosphor surface. 
     
     
       15. The computed tomosynthesis system of  claim 10  wherein at least one of the storage phosphor surfaces comprises a needle phosphor compound. 
     
     
       16. The computed tomosynthesis system of  claim 10  wherein the scan head passes over the storage phosphor surfaces to acquire images from the stored x-ray energy and wherein the scan head comprises an outer housing supporting a light collection assembly and an optical assembly. 
     
     
       17. The computed tomosynthesis system of  claim 16  wherein the scan head is coupled to the gantry assembly such that storage phosphor surfaces may be scanned when the inner hoop is rotated by the inner hoop drive assembly. 
     
     
       18. The computed tomosynthesis system of  claim 16  wherein the scan head is moveable relative to the inner hoop assembly so that the storage phosphor surfaces may be scanned while x-ray exposure is occurring onto other phosphor storage surfaces. 
     
     
       19. The computed tomosynthesis system of  claim 10  wherein the storage phosphor is coated directly onto the surface of the inner hoop. 
     
     
       20. The computed tomosynthesis system of  claim 10  wherein the storage phosphor comprises curved storage phosphor plates coupled to the curved outer surface of the inner hoop assembly.